U.S. Pat. No. 4,077,433 to Maldavs illustrates a piston valve arrangement with a passageway through the valve to assist in assuring that the male ball valve remains open in high flow conditions from the male to the female. U.S. Pat. No. 4,881,573 to Durant illustrates a coupler having two poppet valves. The first poppet engages a ball check valve formed in the male coupling and the second poppet is actuated by a manually operated cam. A passageway exists in the piston to allow fluid to be vented or to pressurize the female valve.
U.S. Pat. No. 4,598,896 to Maldavs illustrates a coupler having a spool and a port within the pool. An annular seal is fixedly positioned about the port in the spool. The spool is slidable with respect to the seal which enables pressure to be relieved in the female during coupling and uncoupling with the male. U.S. Pat. No. 4,303,098 to Shindelar discloses a coupler having a female half which includes a female valve having an elongated stem for engaging the male half. The female half of the coupling is vented by a pivotable cam which moves the inner member of the female half to release its locking means and then opens a poppet valve to open the outlet port.
U.S. Pat. No. 4,249,572 to Shindelar et al. discloses a female half which is self-relieving. The female half includes dual poppet valves which are linked together. One of the poppet valves vents the female half of the coupling when the male and female valves are disengaged and uncoupled.
None of the prior art, however, provides a male half of the coupling which pushes the inner body of the pressurized female half of the coupling (which includes a pressurized chamber between a piston and a relief valve positioning member) causing the positioning member to be displaced in a leftward or rearward direction which causes the venting of the female member. Similarly, the male half of the coupling in the instant invention pulls the inner body of the female half of the coupling rightwardly or forwardly which causes the venting of the female member. Different embodiments of the venting mechanism are disclosed herein.
Also, a manual venting mechanism is disclosed herein. The manual venting mechanism must be operated each time the coupling is made or broken.